1. Field of the Invention
The present invention relates to a dual-sided semiconductor device and a method for forming the device and, more particularly, to a dual-sided semiconductor device and a method for forming the device with a resistive element that requires very little silicon surface area.
2. Description of the Related Art
A dual-sided semiconductor device is a device that has electrical circuits on both sides of a wafer. Thus, unlike more conventional semiconductor devices that utilize only one side of a wafer, a dual-sided device utilizes both sides of the wafer. As a result, packaged dual-sided semiconductor devices consume significantly less circuit-board real estate than conventional single-sided devices.
FIG. 1 shows a cross-sectional drawing that illustrates a dual-sided semiconductor device 100. As shown in FIG. 1, device 100 includes a wafer 110 that has a top side 112 and a bottom side 114. As further shown in FIG. 1, device 100 also has electrical circuits 120 which are formed on top side 112, and electrical circuits 122 which are formed on bottom side 114. Electrical circuits 120 and 122 typically communicate with the outside world via wires that are connected to pads that form a part of circuits 120 and 122.
Thus, as shown in FIG. 1, circuits 120 and 122 both share the central portion of wafer 110. As a result, whatever voltage is present on the central portion of wafer 110 can effect the operation of both circuits 120 and 122. To reduce the likelihood of undesirable effects, the voltage on the central portion of wafer 110 is usually held at a fixed value.
One problem with semiconductor devices is that it is difficult to form large resistive elements on a wafer without consuming large amounts of silicon surface area. The space requirements of large resistive elements are often so severe that external devices must be used. Thus, there is a need for a method of forming large resistive elements on a wafer that consume much less silicon surface area.